This is not a how-to question, more of an opinion question. I have the option of getting some data in either XML or JSON. Which way should I ask for it?

I haven't used either parser but I note there are tools available on CPAN. JSON seems like the "newer, slicker" technology and I find the plaintext JSON files more readable. But neither of those are good reasons for choosing to learn one parser over the other. What are your thoughts, monks?